DCMD_BLK_FORCE_RELEARN, DCMD_FSYS_FORCE_RELEARN
QNX SDP8.0Devctl and Ioctl CommandsDeveloper
Trigger a media reversioning and cache invalidation
Synopsis:
#include <sys/dcmd_blk.h>
#define DCMD_BLK_FORCE_RELEARN __DION(_DCMD_BLK, 2)
#define DCMD_FSYS_FORCE_RELEARN DCMD_BLK_FORCE_RELEARN
Arguments to devctl():
| Argument | Value |
|---|---|
| filedes | A file descriptor that you obtained by opening the device. |
| dcmd | DCMD_BLK_FORCE_RELEARN or DCMD_FSYS_FORCE_RELEARN |
| dev_data_ptr | NULL |
| n_bytes | 0 |
| dev_info_ptr | NULL |
Description:
These commands—which are identical—trigger a
media reversioning and cache invalidation (for removable media).
They're also used to sync-up a filesystem if utilities
play with it behind its back.
In order to use these commands, your process needs to have the vfs/relearn (BLK_ABILITY_RELEARN) custom ability enabled. For more information, see procmgr_ability() and procmgr_ability_lookup() in the C Library Reference.
Input:
None.
Output:
None.
Example:
if ( devctl( fd, DCMD_BLK_FORCE_RELEARN, NULL, 0, NULL ) != EOK)
{
/* Error */
}
See also:
devctl() in the QNX OS C Library Reference
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